import java.util.ArrayList;

public class ArrayList_Demo {
    public static void main(String[] args) {
        ArrayList list = new ArrayList();
        list.add(new Integer(10));
        list.add(20);//20是一个整型变量，进行了一个装箱操作
        list.add(29.98);//自动转换成ddouble类型得了
        list.add("hello");

        list.addAll(list);
        System.out.println("=============");
        for(Object o:list){
            System.out.println(o);
        }
        list.remove(new Integer(20));

        System.out.println("=============");
        for(Object o:list){
            System.out.println(o);
        }
    }
}
